Sound-box



HAROLD Y. PRENDERGAST, 0F NEW YORK, N. Y.

SOUND-BOX.

Specification of Letters Patent.

Patented Apr. 27, 19.20.

Application filed June 18, 1917. Serial No. 175,273.

To all Iwhom, t 'may concern Be it known that I, HAROLD Y. PnnNDnn- GAST, a subject of the King of Great Britain, residing at New York city, in the county of New York and State of New York, have invented new and useful Im provements in Sound-Boxes, of which the followingis a specification.

h/Iy invention relates to sound boxes for talking machines, and its objects are to enhance the volume of sound to improve the quality and clarity of tone, to concentrate the sound vibrations at the sound egress of the box and to effect their more direct transference to the sound arm, to render the stylus bar more flexible and resilient and more responsive to gradations of tone, to prevent the diversion and dissipation of any part of the sound, and in general to simplify and render more effective the operation of the several parts and their accessibility to observation and repair.

My invention primarily consists in the intel-position of a sounding board between theI diaphragm and the sound outlet of the box. 'whereby the quality and clarity of the tonal production is greatly improved.

My invention further consists in effecting a practical separation cf the stylus bar from any portion of the box except where two resilient prongs with annular grooves form a yielding attachment thereto, air spaces being provided at all other portions adjacent to the bar in order to effect free play of the same and to prevent, so far'as possible, any distribution of souid.

My invention further consists in providing a direct passage for the conveyance of sounds from that point of the diaphragm where they are most intense, and also to prevent undesired sound waves from leaving the box and interfering with the sounds conveyed to the ear of the listener through the sound arm.

My invention further consists in effecting a concentration of the sounds at or near the egress passage from the sound box, and

to insure their proper transference to the sound arm.

My invention further consists in the various other modifications and improvements hereinafter more specifically described and claimed.

Attention is hereby directed to the drawing in which similar numerals of designation refer to similar parts throughout the seve 'al views.

Figure l is a view of my improved sound box looking at the same through the transparent closure.

Fig. 2 is a section of the same on line 2 2 of Fig. l, looking in the direction of the arrows.

Fig. 3 is a view of my improved sound box looking at the same at the side opposite to that shown in Fig. l, with the closure 30 removed.

Fig. 4 is a View of the stylus bar.

Fig. 5 is a section of the stylus bar shown in Fig. 4 looking in the direction of the arrow, and

Fig. 6 is al view of a portion' of the stylus bar illustrating one of the prongs.

Referring to the drawing;

lVithin the sound box 7 which is preferably cylindrical in shape and of metal or any other suitable material, I install the sounding board 8, the periphery of which rests upon the annular seat 9.

The sounding board 8 is preferably composed ofwood of the character usually elnployed for musical instruments, but may be made of any suitable material. I prefer to use silver-grained spruce, Aproperly seasoned and varnished in the manner that the same is ordinarily prepared and used in violins or like instruments. In the center of said sounding board S is the circular orifice 10 through which passes the sound coiring from the diaphragm 1l, and which is located opposite the zone of its greatest vibration a washer l2 serving to separate the sounding board and diaphragm and to provide the chamber 13 between the same. By the provision of such chamber I have found that the-toneV of the instrument is greatly improved, both as to quality and distinctness, the sounding board serving to increase the resonance of the sound and to mellow its tone, thereby giving a very characteristic effect.

While as used in my invention, the diaphragm 11 may be of mica or other suitable material. I prefer to use other material than mica such for instance as an opaque diaphragm of fiber composition, which may be colored red or blue, or other distinctive color. and which is susceptible of being printed with the name of the maker or trade mark or embellished in some characteristic manner; a feature which at the present time 1s not possessed by mica because of its brittleness and non-absorptive' qualities.

For the purpose of holding the diaphragm securely in position, I provide the rubber' gasket 14 bent in the form of a circle and compressed by the metallic ring 15 se-,

' 25 secured to the periphery ot the sounding box adjacent thereto and having slots therein registering with the prongs 2?) and 2l, which are secured therein by the screw'svZL and 2st coming in contact with recesses Il() near the ends ot said prongs. In order to prevent any further contact ot the stylus `bar with other portions ol the box than as above described, I provide the slot 2G, which extends through the said supporting plate 25 and the wall and ring adjacent thereto, thereby permitting free play o'l" the said bar within the box and preventing diversion of vibration. s will 'be observed, the arms 21 and 22 are entirely separated `from contact vlth the supporting plate 25 except through the prongs 255 and 2i. Further- .y more, for the purpose ot giving greater resiliency to the bar 2() I also provide the said prongs. with the annular grooves 35, which are adjacent ,to the arms 21 and 22.V

As will be observed, the prongs 225 and 24C extend in a direction which is parallel to the portion ot' the stylus bar within the box, and while being'iirmly secured-to. the plate 25, nevertheless, largelv by reason of the exposed grooves 35 impart considerable resiliency to the stylus bar, thereby renderingfthe same completely responsive to the movements oiI thc stylus `in a manner l'ieretol'ort-i unknown in the art. .Preferably the said prongs are o'l sullicient stiffness as not to be resilient except as so rendered by reason of the grooves 55. As is obvious by my new construction, l. dispense cntirely with the hinge, pivotal, iam uut connections heretofore usually employed in prior operative structures to secure the stylus bar to the sound box, and thereby obviatc any sounds produced in the movement olf such connections. Also by having the attachment of two prongs grooved as aforesaid and equidistant i'rom the axis ol the bar, greater steadiness and balance are imparted to the same.

`come in contact with it.

The outer end of the stylus bar is furnished with the usual socket 2T and retaining screw 28, provided for the reception of the stylus 29 and operating in the usual manner.

At one side of the sound box, I provide the detachable cover ISU; the periphery of which is attached'to the sound. box by means of the screws il and the center oi which is provided with the walled passage 32, arranged to connect with the sound arm (not shown) in the usual manner. li" desired, the cover il() may be made integral with the wall ot the sound box and thereby dispense with the screws ill.

ln ordcr to insure the proper conduction ot' sounds through the orifice l() ol" the sounding board H, which are gathered from the chamber 13, I provide the cover' 3() with theannula r recess 33, within which is seated the rubber gasket $54, engaging with the sur lace ot' the .sounding board in close proximityr with the oril'ice l0. ly such arrangement it is to be noticed that all vibrations ol' .sound collected from said chamber 13 are concentrated at and conducted through the orilice l0, and the walled passage 32.

As will be uiulerstood, the screws 1G pass through openings in both the wall of the box and the ring l5. Since the normal diameter ot' the ring is sn'ialler than that of the bore of the box, such diameter may be increased by tightening ot the screws 16, inV which event the wall ot the ring 15 is dran n closer to the wall 4 o't' the box, and may even Where the ring touches the wall ot the box, it is obviously at its greatest diameter andy such diameter may be reduced by loosening the screws 16, in which event the ring 15 will Spring away 'lrom the wall of the box. Consequently, the ring 15 may, by means of the screws 16, loe adjusted to various t'liameters and thereby aliect the loose or tight engagement with the groove 17 as may be desired.

ln order that the sounding board bel kept in proper shape andl comlition, particularly when made ot' wood, I prefer to employ the cleats 37 which extend across the grain of the wood and are firmly secured thereto in any suitable manner, such cleats, however, I do not regard as absolutely essential to the operation ol such sounding board.

While I have described my invention with particular reference to its embodiment in the l'n'eterred i'orm of construction above forth, I do not desire to be understood as confining the scope of my invention to the details o't construction herein set forth, since, as is obvious, various modifications and changes may be elfected Without cle-1 parting from the spirit thereof.

What 1 claim and desire to secure by Lettcrs Patent is:

1. A sound box embodying a casing havlng'board posltioned within the casing in spaced relation to one another and supported `therein at their outer peripheries to provide an intermediate sound chamber, said sounding board being provided at its center with an aperture located opposite the zone of `greatest amplitude of vibration of the diaphragm, and in alinement with the sound outlet of the casing,vand 'an annular yieldable member, of substantially the same interior diameter as the aperture in the sounding board, clamped between, the sounding board and the Wall of the sound box to pro` vide a continuous passage from the sound chamber to the outlet ot' the sound box, all parts of said sounding board, except its periphery, being free to vibrate.

A sound box embodying a casing, a diaphragm and a sounding board peripherally secured within said easing and spaced apart to provide a'n intermediate sound chamber, the sounding board being provided with a central aperture, and the easing being similarly provided with an alined sound outlet, and a resilient flexible and yielda-ble connection from the aperture in the sounding board to the outlet of the sound box to provide a continuous passage from the sound chamber out of the easing, said eonneetlon being 1n -the form of a rubber ring clamped between the-sounding board and the wall of the easing, and having an inner diameter substantially equal to the diameter` of the aperture in the sounding board.

3. A sound box embodying a Casin a diaphragm and a sounding board perip erally secured. within said casing and -spaced apart to provide an' intermediate sound chamber, th'e sounding'board being provided with a central aperture, and the casing being similarly provided with an alined sound outlet, and a resilient iexible and yleldable connection from the aperture in'the sounding board to the outlet of the sound box to provide a continuous passage from the sound ehamber out of the easing, said connection being in the form of a resilient ring having an inner diameter substantially equal to the diameter of the aperture of the sounding board, said ring being seated in the recess in the wall of the casing to maintain it co-axal with the aperture in the sounding board and clamped between the sounding board and the easing. i

In testimony whereof I have hereunto set my hand in presence of two subscribing Witnesses, thi, 16th day or' June, 1917.

HAROLD PRENDERGAST.

Witnesses:

FRANK B. VERMILYA, GEO. D. DE LUCA. 

